The Role of Water in the Oligomerization Equilibria Involving Bis(pentafluorophenyl)borinic Acid in Dichloromethane Solution
作者:Tiziana Beringhelli、Giuseppe D'Alfonso、Daniela Donghi、Daniela Maggioni、Pierluigi Mercandelli、Angelo Sironi
DOI:10.1021/om0494519
日期:2004.11.1
The 1H, 19F, and 11B NMR data indicated that in CD2Cl2 solution monomeric bis(pentafluorophenyl)borinic acid, (C6F5)2BOH (1m), is in equilibrium with the cyclic trimer (1t) observed in the solid state. The position of the association equilibrium shifted to the right on increasing the concentration, on decreasing the temperature, and on decreasing solvent polarity, in the series CD2Cl2, CDCl3, CCl4
的1 H,19 F和11个乙NMR数据表明,在CD 2氯2溶液的单体的双(五氟苯基)硼酸,(C 6 ˚F 5)2 BOH(1米),与所述环状三聚体平衡(1 t)在固态下观察到。在CD 2 Cl 2,CDCl 3,CCl 4系列中,随着浓度的增加,温度的降低以及溶剂极性的降低,缔合平衡的位置向右移动。,与单体的较高极性(根据PM3计算,为2.38 D表示1 m,0.65 D表示1 t)相一致。在低于210 K的温度下,1 H和19 F NMR光谱显示同时(可逆)形成了两种新型化合物,它们被配制成(C 6 F 5)2 BOB(C 6 F 5)2酸酐(2)和三聚体[[C 6 F 5)2 BOH] 3 ·OH 2(3),C 2对称,将水分子正式插入1 t的B-O(H)-B桥中,得到非常强的BO(H)··HO(H)B氢键(δ18.6)。184 K的1 H和19 F EXSY实验表明交换在3和1 m之间,而不是1